Process for preparing liquid detergent



United States Patent 3,549,546 PROCESS FOR PREPARING LIQUID DETERGENTRobert S. Moore, Wyoming, Ohio, assignor to The Procter & GambleCompany, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Oct.2, 1967, Ser. No. 671,960 Int. Cl. Clld 1/38, 1/65, 1/62 U.S. Cl. 2521522 Claims ABSTRACT OF THE DISCLOSURE A process for preparing ahomogeneous liquid detergent composition containing an anionic organicdetergent and a cationic polymer, consisting of dissolving an aqueoussolution of the polymer in triethanolamine; dispersing thepolymer-triethanolamine solution in an aqueous solution of anionicorganic detergent using low shear mixing means; and milling theresultant mixture in a closed system colloid mill.

Liquid detergent compositions, especially shampoo compositions,generally contain an anionic organic synthetic detergent as theprincipal ingredient. Cationic polymeric substances are desirablyincorporated in such compositions for various purposes. For example,anionic organic detergent compositions containing various cationicpolymeric substances are disclosed by Lang and McCune in U.S. LettersPatent 3,313,734, granted Apr. 11, 1967. The cationic polymers areemployed in that patent to improve hair condition, i.e., wave setretention and hair manageability. Lang, U.S. patent application Ser. No.586,013, filed Oct. 12, 1966 now Pat. No. 3,400,198, discloses anionicorganic detergent compositions containing still other cationic polymersas hair conditioning additives.

Yet another invention which involves the use of cationic polymers in ananionic organic detergent product is disclosed by Parran, U.S. patentapplication Ser. No. 476,175, filed July 30, 1965 now abandoned. Thedetergent compositions of the Parran invention contain cationic polymersto promote deposition and retention of particulate substances, e.g.,antidandruff agents, on surfaces washed with the composition.

Because of the well known incompatibility of anionic organic detergentsand cationic polymeric substances, special measures must be taken toprepare stable homogeneous produces containing these materials.

As taught in the aforementioned disclosures, certain ampholytic andpolar nonionic detergents serve to compatibilize cationic polymers andanionic detergents. However, such ancillary detergents are relativelyexpensive and manufacturing efficiency and quality control areunfavorably affected by complicating the formulation with thesematerials.

Apparently stable homogeneous liquid products containing both cationicpolymers and anionic detergents can be prepared without such ancillarydetergents by using high shear mixing techniques followed by milling ina colloid mill; however, such mixing can result in aeration of theproduct which ultimately causes visible separation of the ingredients.

It is an object of this invention to provide an improved method forpreparing a liquid detergent composition Patented Dec. 22, 1970containin an anionic organic detergent and a cationic polymer.

It is a further object of this invention to provide a method forpreparing a stable homogeneous liquid detergent composition containing acationic polymer and an anionic detergent, which is essentially free ofentrapped am It is a still further object of this invention to provide amethod for preparing a stable homogeneous liquid detergent compositioncontaining a cationic polymer and an anionic detergent without usingancillary ampholytic or polar anionic detergents to compatibilize same.

These and other objects are accomplished by the invention hereinafterdescribed and claimed.

In general terms, this invention comprises a process for preparingstable homogeneous liquid detergent compositions containin an anionicorganic detergent and a cationic polymer comprising the steps of (1)dissolving an aqueous solution of said polymer in triethanolamine; (2)dispersing the resulting solution in an aqueous solution of saiddetergent using low shear mixing means to prevent aeration; and (3)milling the resulting dispersion in a sealed colloid mill equipped withenclosed feed and discharge means.

It has been discovered that by dissolving the cationic polymer intriethanolamine prior to adding same to the anionic organic detergentcomponent, a surprisingly uni form dispersion of the polymer is obtainedwith only mild agitation (low shear mixing). It is, of course, essentialthat the mixture be uniformly dispersed prior to milling in a colloidmill and this could heretofore be accomplished only by high shear mixingwith attendant aeration.

Compositions prepared in accordance with the process of this inventioncontain, as hereinbefore stated, an anionic organic detergent such aswater-soluble soaps and nonsoap synthetic detergents. Operable nonsoapanionic organic detergents include, for example, watersoluble salts oforganic sulfuric reaction products having in their molecular structurean alkyl containing from about 8 to about 20 carbon atoms and a sulfonicacid or sulfuric acid ester group. Important examples of this type ofnonsoap anionic synthetic detergent, include the sodium or potassiumalkyl sulfates, including those derived by sulfation of higher alcoholsproduced by reduction of tallow or coconut oil glycerides; sodium orpotassium alkylbenzene sulfonates, especially those of the typesdescribed by Guenther et al. in US. Pat. 2,220,099, granted Nov. 5,1940, and by Lewis in U.S. Pat. 2,477,- 383, granted July 26, 1949, inwhich the alkyl group contains from about 9 to about 15 carbon atoms;sodium alkylglyceryl ether sulfonates, especially those ethers of higheralcohols obtained from tallow and coconut oil; sodium coconut oil fattyacid monoglyceride sulfates and sulfonates; sodium andtriethanolammonium salts of sulfuric acid esters of the reaction productof one mole of a higher fatty alcohol (i.e., tallow or coconut oilalcohols) and about 3 moles of ethylene oxide; and others well known inthe art, a number being specifically set forth in Byerly, U.S. Pat. Nos.2,486,921 and 2,486,922.

Additional nonsoap anionic organic synthetic detergents which can beused in this invention include the salts of the condensation products offatty acids with sarcosinate, i.e., acyl sarcosinate, wherein the acylradical has a chain length range from about 10 to 18 carbon atoms. Anespecially preferred acyl sarcosinate for the purpose of this inventionis sodium lauroyl sarcosinate.

Preferably, the nonsoap anionic organic detergent will be of the highsudsing type as for example, the alkyllglycerylether sulfonates, thesulfated fatty alcohols or the alkyl ether ethylene oxide sulfateswherein the ethylene oxide chain averages 3 units, and acylsarcosinates, all as more fully set forth above. These and the foregoingdetergents can be used in the form of their sodium potassium or loweralkanolamine (such as triethanolammonium) salts.

Conventional soaps may also be used as the anionic detergent componentof this invention. Suitable soaps include the sodium, potassium, andlower alkanolamine salts of higher fatty acids of naturally occurringvegetable or animal fats and oils. For example, sodium, potassium andtriethanolamine salts of fatty acids occurring in coconut oil, soybeanoils, castor oil, tallow or synthetically produced fatty acids may beused.

If soap is to be used, it would desirably be used in small quantities,less than about and would be admixed with nonsoap anionic detergents toform the final detergent component of the compositions of thisinvention. Preferably, the triethanolammonium salt of coconut fatty acidwould be used, since it is more readily soluble than the salts of higheralkyl chain length fatty acids. Other preferred soaps include the sodiumand potassium salts of coconut fatty acid.

Mixtures of any of the foregoing anionic detergents may also be used inthe composition of this invention.

The anionic organic detergent can be employed in concentrations rangingfrom about 4% to about 30% by weight of the total composition with thepreferred range being from about 7% to about Because of the excellentsolubility and lathering properties of anionic nonsoap detergentscontaining predominantly C and C alkyl chain lengths and their readyavailability, these are preferred for the purpose of this invention.

The cationic polymers which can be incorporated in detergentcompositions through the practice of this invention includewater-soluble polymers at least mole percent of the molecular structuresof which are composed of monomeric units containing one or morequaternary ammonium groups and any balances of which are comprised ofnonquaternized polymeric units derived from monoethylenicallyunsaturated groups. Such polymers include, for example, quaternizedpolyvinylimidazole, quaternized poly(dimethylaminoethylmethacrylate),quaternized poly(diethylaminoethylmethacrylate), quaternizedpoly(p-dimethylaminomethylstyrene) and others disclosed in US. Pat.3,313,734 having molecular weights of from about 1,000 to about5,000,000.

Yet other cationic polymers are those disclosed by Parran in U.S.application Ser. No. 476,175, filed Jufy 30, 1965, i.e.,polyethylenimine or alkoxylated polyethylenimine having a molecularweight greater than about 100 but less than about 5,000,000.

Still other cationic polymers which can be added to anionic detergentsby the process of this invention are l) the water-soluble quaternarynitrogen-substituted cellulose derivatives available under the codedesignation JR1L; (2) the water-soluble linear polyamines availableunder the trade name Primafioc, and related polymers disclosed in US.Letters Pat. 3,300,406, granted Jan. 24, 1967; and (3) the water-solublepolymers of epichlorohydrin and tetraethylene-pentamine available underits trade name Nalco 600. All of these latter polymers are water-solublecationic tertiary amine or quaternary ammonium-containing polymershaving molecular weights within the range from about 2,000 to 3,000,000,and having a cationic charge density 0 Number of positive charges) Unitmolecular Weight greater than about 0.001

It can be seen that the present invention finds application inconnection with the addition of any cationic polymer to any anionicorganic detergent in a liquid form. Thus, the specific nature of theinvolved cationic polymer is not critical. Rather, it is the inherentincompatibility of cationic materials generally with anionic detergentsthat renders the present invention useful in its broadest aspect.

The cationic polymer can be incorporated in detergent compositions ofthe type herein contemplated at concentrations ranging from about 0.1%to about 7.0% by Weight. The optimum concentrations will vary dependingon the type of polymer employed and its intended purpose in thecomposition. Detergent compositions containing more than about 7.0% ofcationic polymer are difficult to formulate without high shear mixingand concomitant aeration of the product. Concentrations of cationicpolymer less than about 0.1% do not generally provide the desired effectin the composition.

Aside from the purposes of the present invention, triethanolamine hasbeen included in detergent compositions for a variety of purposes. Forexample, it is a base which can be used to adjust the pH of suchcompositions and is especially suited for this use in compositionswherein the organic anionic detergent is a triethanolammonium salt. Inthe process of the present invention this material additionally providesa vehicle for introduction of a cationic polymer into an anionic organicdetergent to permit uniform dispersion of the polymer.

In the practice of this invention, an aqueous solution of the cationicpolymer is dissolved in triethanolamine in quantities sufficient toprovide the desired ultimate concentration of each of these materials inthe finished detergent composition. Preferably, the aqueous solution ofpolymer is in a concentration range of from about 1.0% to about 50.0%,more preferably about 40.0%, when mixed with the triethanolamine. Thetriethanolamine concentration in the aqueous solution of polymer andtriethanolamine is desirably within the range from about 15% to aboutand best results are obtained when this component is employed at aconcentration of about 40% in the polymer/triethanolamine aqueoussolution.

The polymer/triethanolamine solution is maintained at a temperaturewithin the range from about 50 to 200 F. and is thoroughly mixed. Thissolution is then added to an aqueous solution of the anionic detergent,preferably at a concentration of from about 4% to about 60%, togetherwith other desired components in a main mix tank equipped with low shearmixing means. Although temperatures are not critical, the anionicdetergent solution is preferably heated to a temperature in the rangefrom about F. to about F. prior to the addition of the cationicpolymer/triethanolamine solution. After sufficiently mixing to effectuniform dispersion of all ingredients, the mixture is milled in a closedsystem colloid mill.

The terms low shear mixing and low shear agitation are usedinterchangeably herein and refer to means and/ or methods for dissolvingor dispersing the ingredients of the involved compositions which do notaerate the compositions to any substantial degree. Any of the well knowncommercial propeller or turbine type agitators can be used, if operatedat speeds or adjustments which will not lead to the entrapment of airbubbles.

The closed system colloid mill specified for use in the present processis available in a variety of designs from a number of manufacturers. Theterm closed system used herein to characterize such mills refers to theair-tight inlet and discharge means which precludes the introduction ofatmospheric air during the milling procedures. A general discussion ofcolloid mills and other mixing means is found in Sagarin, CosmeticsScience & Technology, pages 1020-1022 (Interscience Publishers, Inc.,1957).

The process of this invention is fully illustrated by rcference to thefollowing examples which are not to be construed as limiting theinvention in any way.

EXAMPLE I A liquid detergent formulation of the following compositionwas prepared using the process of this invention.

Component: Percent by weight Triethanolamine coconut sulfate 20.00

Triethanolamine 1.60 Zinc 2-pyridinethiol-l-oxide 1.00 Polyethylenimine/propylene oxide reaction product 2 1.00 Hydroxypropoxyl substitutedmethyl cellulose 3 0.24 Coconut 1 monoethanolamine 4.00 Veegum 4 0.95Coloring 0.10 Perfume 0.25 Distilled water Balance The term coconut asused herein refers to alkyl groups which are derived from the middlecutof coconut alcohol having the following approximate chain lengthdistribution: 2%-C1o; 66%-C12; 23%C14; and 9%C1e.

Polyethylenimine having a molecular weight of 40,000 to 60,030;1 moleratio of polyethylenimine to propylene oxide lw ethbcel 60 HG comprisedof from 28% to 30% by weight of methoxyl and from 7% to 12% by weight ofhydroxypropoxyl substituents. Degree of substitution with methoxyl andhydroxypropoxyl substitueuts is 1.68 to 1.82 and from 0.17 to 0.3,respectively.

Complex colloidal magnesium aluminum silicate.

The above composition was prepared as follows: 40.0 grams of a 50%aqueous solution of the propylene oxide/ polyethylenimine was added to32 grams of triethanolamine and mixed at room temperature in a 100 ml.beaker with an air operated stirrier with a two-bladed propeller-typeagitator operated at low speed until a single phase solution was formed.

The polymer/triethanolamine solution was then added to 1111.2 grams of a36% aqueous solution of triethanolammonium coconut sulfate heated to 160F. to '190" F. in a steam-jacketed, stainless steel main mix tankequipped with a Lightnin mixer having a 2" diameter turbine operated atapproximately 50 rpm. 40.0 grams of a 50% aqueous dispersion of zincZ-pyridinethiol-l-oxide, 88.8 grams of a 4.5% aqueous solution ofhydroxypropoxyl-substituted methylcellulose, and 80.0 grams of coconutmonoethanolamide were also added to the main mix tank.

361 grams of distilled water were heated to 180 F. to 210 F. and 19.0grams of Veegurn were slowly added thereto in a Waring blender operatedto provide a vortex to the bottom of the mixing chamber. The Veegum wasallowed to hydrate for one hour with agitation and was then added to themain mix tank.

The remaining ingredients were added to the main mix tank and the totalcomposition was mixed with low shear for minutes. The mixture was thenmilled at .002 inch gap in a Gaulin colloid mill having sealed feed anddischarge ports to prevent introduction of atmospheric air during themilling operation.

The milled product was cooled to 80 F. This liqiud detergent compositionwas found to be stable and homogeneous and essentially free of entrappedair bubbles.

EXAMPLE II A composition was prepared identical in formulation to thecomposition of Example I, except that the polyethylenimine/propyleneoxide was replaced with an ethoxylated polyethylenimne (polyethyleniminehaving a molecular weight of 40,000 to 60,000; weight ratio ofpolyethylenimine to ethylene oxide equals 1:1; and total molecularweight 80,000 to 120,000) and the anionic detergent constituted 21% byweight of the composition rather than as in Example I. The procedureemployed in the preparation of this composition was the same as ExampleI except the aqueous polymer/triethanolamine solution was added to themain mix tank. The product was again a stable homogeneous liquiddetergent, essentially free of entrapped air.

EXAMPLE III Formulations identical to those prepared in Examples I andII but containing triethanolamine dodecylbenzene sulfonate; potassiumcoconut glyceryl ether sulfonate; the sodium and triethanolammoniumsalts of the sulfated condensation product of 1 mole of coconut fattyalcohol and 3 moles of ethylene oxide, and sodium lauroyl sarcosinate,respectively, in place of triethanolamine coconut sulfate, areformulated in accordance with the process of Example I. The resultingproducts are stable homogeneous liquids essentially free of entrappedair.

EXAMPLE IV Additional compositions are prepared in accordance with theprocedure of Example I but using a substantially completely quaternizedpolyvinylimidazole, having a molecular range of about 100,000; dimethylsulfate quarternized poly (diethylaminoethyl methacrylate) having ing amolecular weight of about 500,000 and prepared in accordance withExample I of US. 2,723,256 granted Nov. 8, 1955; substantiallycompletely quarternized poly (p-dimethylaminomethylstyrene) having amolecular weight of approximately 250,000; substantially completelymethyl phosphate quaternized poly(dimethylaminoethyl methacrylate)having a molecular weight within the range a molecular Weight of about500,000 and prepared scribed; Nalco 600 as hereinbefore described;Primafioc as hereinbefore described; and a water-solublepolyethylenimine having an average molecular weight of about 100,000 anda viscosity of 2.5 centipoises in a 1% by weight aqueous solution;respectively, in place of the alkoxylated polyethylenimine. Theresulting products are stable homogeneous liquids which are relativelynonaerated.

Unless otherwise specified, the percentage values employed herein referto percent by weight.

Although the formulations set forth herein in the examples include anumber of ancillary ingredients, it is to be understood that the processdescribed and claimed herein is useful in the preparation of stablehomogeneous liquid detergents containing any desired organic anionicdetergent and cationic polymer without regard to other ingredients.

What is claimed is:

1. A method for preparing a stable, homogeneous liquid detergentcomposition consisting essentially of (a) a cationic polymer selectedfrom the group consisting of polyethylenimine, alkoxylatedpolyethylenimine prepared by reacting polyethylenimine with alkyleneoxide compounds which contain from about 2 to about 3 carbon atoms,quanternized polyvinylimidazole, quaternized poly(diethylaminoethylmethacrylate), quaternizedpoly(dimethylaminoethylmethacrylate), and quaternizedpoly(pdimethylaminomethylstyrene), said polyethylenimine and alkoxylatedpolyethylenimine having a molecular weight greater than 100, but lessthan 500,000, and said quaternized compounds having a molecular weightof from about 1,000 to 5,000,000 and (b) an anionic organic detergent,comprising the steps of (l) admixing an aqueous solution of saidcationic polymer at a concentration within the range from about 1% toabout 50% with triethanolamine in a quantity sufficient to provide aconcentration of triethanolamine in the mixture within the range of fromabout 15% to about (2) dispersing the resulting mixture in an aqueoussolution of said anionic organic detergent at a concentration within therange of from about 4% to about 50% by weight and at a temperaturewithin the range of from about F. to about F., using low shear mixingmeans to prevent aera- 8 tion; and (3) milling the resulting dispersionin a sealed References Cited colloid mill having enclosed feed anddischarge means. UNITED STATES PATENTS 2. A method in accordance withclaim 1 wherein the 2 914 482 11/1959 pp 252 152 a n n n d organicanionic detergent 1s a Water soluble etergent sa 3,150,098 9/1964 Wilson252152 of a member selected from the group consisting of higher 5 fattacids, anionic or anic sulfuric reaction roducts hav lng in theirmolecul ar structure an alkyl co ntaining LEON ROSDOL Pnmary Exammerfrom about 8 to about 20 carbon atoms and a sulfonic M. L. HALPERN,Assistant Examiner acid or sulfuric acid ester group, and acylsarcosinates wherein the acyl group contains from about 10 to about 10XR 18 carbon atoms. 252137 22 33 UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION Patent No. 549,546 D t d December 22 1970 Invencoz ei)Robert S. Moore It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 49, "produces" should read -products-- Column 3, lines 9and 10, after "sodium" and before "potassium" should read Column 3, line56, "5,000,000" should read --500,o00--.

Column 3, line 75, after '0 .001" should read Column 5, line 68,"polyethylenimne" should read -polyethyleni Column 6, line 22 "quar-"should read --qua- Column 6, line 26, "quarternized" should read--quaternized--.

Column 6, lines 31 and 32 "a molecular weight of about 500,000 andprepared scribed" should be deleted, and from about 1 ,000 to 5,000,000;JR-lL as hereinbefore described inserted theref Column 6, line 56,"quanternized" should read -quaternized-.

Signed and sealed this 1 th day of May 1 971 (SEAL) Atteat: I

EDWARD M.FLETGHER.JR. WILLIAM E. SGHUYLER, Attesting OfficerCommissioner of Pater]

